Testing sources of variation in nestling-stage nest success of Florida Scrub-Jays in suburban and wildland habitats

    Authors

    J. M. Niederhauser;R. Bowman

    Comments

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    Abbreviated Journal Title

    J. Field Ornithol.

    Keywords

    Aphelocoma coerulescens; food supplementation; human modification; nest; survival; nestling begging; parental care; predation risk; ANNUAL REPRODUCTIVE SUCCESS; LIFE-HISTORY EVOLUTION; FOOD; SUPPLEMENTATION; PREDATION RISK; URBAN GRADIENT; SONG SPARROWS; APHELOCOMA COERULESCENS; INVESTMENT STRATEGIES; BEGGING BEHAVIOR; PARENTAL CARE; Ornithology

    Abstract

    Human modification of habitats can reduce reproductive success by providing novel cues to which birds may respond with behaviors that are actually maladaptive in those environments. Ad libitum human-provided foods may provide the perception that urban habitats are food-rich even as natural food availability decreases. Similarly, human activity may increase the perception that predation risk is high even as natural predators may decrease in abundance. In response, birds may reduce parental care with a subsequent cost to successful reproduction. Florida Scrub-Jays (Aphelocoma coerulescens) in suburban areas have lower nest success during the nestling period than do wildland jays, possibly the result of such maladaptive responses, but maybe because of ecological differences with wildlands. We manipulated adult perception of predation risk and the availability of nestling foods in suburban and wildland areas to determine if these factors influenced parental care and nestling begging, and if the behavioral responses of adults influence nest survival during the nestling stage. Experimentally increasing perception of predation risk reduced parental care by both suburban and wildland females, but did not influence care by males. Increasing food availability, but not predation risk, had little influence on parental care, but resulted in decreased nestling begging rates and an increase in the frequency (pitch) of begging calls in both habitats. However, neither parental care nor food availability influenced nest survival during the nestling stage. Instead, the presence of helpers was the most important variable in nest survival analyses, suggesting that habitat-specific differences in nest survival during the nestling stage were not simply the result of maladaptive parental behavior or shortage of nestling food resources in the suburban habitat. The lack of helpers combined with ecological differences, such as the abundance of nest predators, may be why fewer nests of Florida Scrub-Jays survive during this stage in suburban areas.

    Journal Title

    Journal of Field Ornithology

    Volume

    85

    Issue/Number

    2

    Publication Date

    1-1-2014

    Document Type

    Article

    Language

    English

    First Page

    180

    Last Page

    195

    WOS Identifier

    WOS:000340612600005

    ISSN

    0273-8570

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